Package org.apache.zookeeper.server

Class ZKDatabase

java.lang.Object

org.apache.zookeeper.server.ZKDatabase

public class ZKDatabase
extends java.lang.Object

This class maintains the in memory database of zookeeper server states that includes the sessions, datatree and the committed logs. It is booted up after reading the logs and snapshots from the disk.

Field Summary

Fields

Modifier and Type	Field	Description
protected static int	commitLogBuffer
static int	commitLogCount
protected java.util.LinkedList<Leader.Proposal>	committedLog
protected DataTree	dataTree	make sure on a clear you take care of all these members.
protected java.util.concurrent.locks.ReentrantReadWriteLock	logLock
protected long	maxCommittedLog
protected long	minCommittedLog
protected java.util.concurrent.ConcurrentHashMap<java.lang.Long,java.lang.Integer>	sessionsWithTimeouts
protected FileTxnSnapLog	snapLog

Constructor Summary

Constructors

Constructor	Description
ZKDatabase(FileTxnSnapLog snapLog)	the filetxnsnaplog that this zk database maps to.

Method Summary

Modifier and Type	Method	Description
java.util.List<ACL>	aclForNode(DataNode n)
void	addCommittedProposal(Request request)	maintains a list of last committedLog or so committed requests.
boolean	append(Request si)	append to the underlying transaction log
void	clear()	clear the zkdatabase.
void	close()	close this database.
void	commit()	commit to the underlying transaction log
void	deserializeSnapshot(org.apache.jute.InputArchive ia)	deserialize a snapshot from an input archive
void	dumpEphemerals(java.io.PrintWriter pwriter)	write a text dump of all the ephemerals in the datatree
long	fastForwardDataBase()	Fast forward the database adding transactions from the committed log into memory.
java.util.List<ACL>	getACL(java.lang.String path, Stat stat)	get acl for a path
int	getAclSize()	get the acl size of the datatree
java.util.List<java.lang.String>	getChildren(java.lang.String path, Stat stat, Watcher watcher)	get children list for this path
java.util.LinkedList<Leader.Proposal>	getCommittedLog()
byte[]	getData(java.lang.String path, Stat stat, Watcher watcher)	get data and stat for a path
DataTree	getDataTree()	the datatree for this zkdatabase
long	getDataTreeLastProcessedZxid()	get the last processed zxid from a datatree
java.util.HashSet<java.lang.String>	getEphemerals(long sessionId)	the paths for ephemeral session id
java.util.concurrent.locks.ReentrantReadWriteLock	getLogLock()	Get the lock that controls the committedLog.
long	getmaxCommittedLog()	the committed log for this zk database
long	getminCommittedLog()	the minimum committed transaction log available in memory
DataNode	getNode(java.lang.String path)	get the datanode for this path
int	getNodeCount()	the node count of the datatree
java.util.Collection<java.lang.Long>	getSessions()	return the sessions in the datatree
java.util.concurrent.ConcurrentHashMap<java.lang.Long,java.lang.Integer>	getSessionWithTimeOuts()	get sessions with timeouts
boolean	isInitialized()	checks to see if the zk database has been initialized or not.
boolean	isSpecialPath(java.lang.String path)	check if the path is special or not
void	killSession(long sessionId, long zxid)	kill a given session in the datatree
long	loadDataBase()	load the database from the disk onto memory and also add the transactions to the committedlog in memory.
DataTree.ProcessTxnResult	processTxn(TxnHeader hdr, org.apache.jute.Record txn)	the process txn on the data
void	removeCnxn(ServerCnxn cnxn)	remove a cnxn from the datatree
void	rollLog()	roll the underlying log
void	serializeSnapshot(org.apache.jute.OutputArchive oa)	serialize the snapshot
void	setDataTreeInit(boolean b)	set the datatree initialized or not
void	setlastProcessedZxid(long zxid)	the last processed zxid in the datatree
void	setWatches(long relativeZxid, java.util.List<java.lang.String> dataWatches, java.util.List<java.lang.String> existWatches, java.util.List<java.lang.String> childWatches, Watcher watcher)	set watches on the datatree
Stat	statNode(java.lang.String path, ServerCnxn serverCnxn)	stat the path
boolean	truncateLog(long zxid)	Truncate the ZKDatabase to the specified zxid

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

dataTree

protected DataTree dataTree

make sure on a clear you take care of all these members.

sessionsWithTimeouts

protected java.util.concurrent.ConcurrentHashMap<java.lang.Long,java.lang.Integer> sessionsWithTimeouts

snapLog

protected FileTxnSnapLog snapLog

minCommittedLog

protected long minCommittedLog

maxCommittedLog

protected long maxCommittedLog

commitLogCount

public static final int commitLogCount

See Also:

Constant Field Values

commitLogBuffer

protected static int commitLogBuffer

committedLog

protected java.util.LinkedList<Leader.Proposal> committedLog

logLock

protected java.util.concurrent.locks.ReentrantReadWriteLock logLock

Constructor Detail

ZKDatabase

public ZKDatabase(FileTxnSnapLog snapLog)

the filetxnsnaplog that this zk database maps to. There is a one to one relationship between a filetxnsnaplog and zkdatabase.

Parameters:

snapLog - the FileTxnSnapLog mapping this zkdatabase

Method Detail

isInitialized

public boolean isInitialized()

checks to see if the zk database has been initialized or not.

Returns:

true if zk database is initialized and false if not

clear

public void clear()

clear the zkdatabase. Note to developers - be careful to see that the clear method does clear out all the data structures in zkdatabase.

getDataTree

public DataTree getDataTree()

the datatree for this zkdatabase

Returns:

the datatree for this zkdatabase

getmaxCommittedLog

public long getmaxCommittedLog()

the committed log for this zk database

Returns:

the committed log for this zkdatabase

getminCommittedLog

public long getminCommittedLog()

the minimum committed transaction log available in memory

Returns:

the minimum committed transaction log available in memory

getLogLock

public java.util.concurrent.locks.ReentrantReadWriteLock getLogLock()

Get the lock that controls the committedLog. If you want to get the pointer to the committedLog, you need to use this lock to acquire a read lock before calling getCommittedLog()

Returns:

the lock that controls the committed log

getCommittedLog

public java.util.LinkedList<Leader.Proposal> getCommittedLog()

getDataTreeLastProcessedZxid

public long getDataTreeLastProcessedZxid()

get the last processed zxid from a datatree

Returns:

the last processed zxid of a datatree

setDataTreeInit

public void setDataTreeInit(boolean b)

set the datatree initialized or not

Parameters:

b - set the datatree initialized to b

getSessions

public java.util.Collection<java.lang.Long> getSessions()

return the sessions in the datatree

Returns:

the data tree sessions

getSessionWithTimeOuts

public java.util.concurrent.ConcurrentHashMap<java.lang.Long,java.lang.Integer> getSessionWithTimeOuts()

get sessions with timeouts

Returns:

the hashmap of sessions with timeouts

loadDataBase

public long loadDataBase()
                  throws java.io.IOException

load the database from the disk onto memory and also add the transactions to the committedlog in memory.

Returns:

the last valid zxid on disk

Throws:

java.io.IOException

fastForwardDataBase

public long fastForwardDataBase()
                         throws java.io.IOException

Fast forward the database adding transactions from the committed log into memory.

Returns:

the last valid zxid.

Throws:

java.io.IOException

addCommittedProposal

public void addCommittedProposal(Request request)

maintains a list of last committedLog or so committed requests. This is used for fast follower synchronization.

Parameters:

request - committed request

aclForNode

public java.util.List<ACL> aclForNode(DataNode n)

removeCnxn

public void removeCnxn(ServerCnxn cnxn)

remove a cnxn from the datatree

Parameters:

cnxn - the cnxn to remove from the datatree

killSession

public void killSession(long sessionId,
                        long zxid)

kill a given session in the datatree

Parameters:

sessionId - the session id to be killed

zxid - the zxid of kill session transaction

dumpEphemerals

public void dumpEphemerals(java.io.PrintWriter pwriter)

write a text dump of all the ephemerals in the datatree

Parameters:

pwriter - the output to write to

getNodeCount

public int getNodeCount()

the node count of the datatree

Returns:

the node count of datatree

getEphemerals

public java.util.HashSet<java.lang.String> getEphemerals(long sessionId)

the paths for ephemeral session id

Parameters:

sessionId - the session id for which paths match to

Returns:

the paths for a session id

setlastProcessedZxid

public void setlastProcessedZxid(long zxid)

the last processed zxid in the datatree

Parameters:

zxid - the last processed zxid in the datatree

processTxn

public DataTree.ProcessTxnResult processTxn(TxnHeader hdr,
                                            org.apache.jute.Record txn)

the process txn on the data

Parameters:

hdr - the txnheader for the txn

txn - the transaction that needs to be processed

Returns:

the result of processing the transaction on this datatree/zkdatabase

statNode

public Stat statNode(java.lang.String path,
                     ServerCnxn serverCnxn)
              throws KeeperException.NoNodeException

stat the path

Parameters:

path - the path for which stat is to be done

serverCnxn - the servercnxn attached to this request

Returns:

the stat of this node

Throws:

KeeperException.NoNodeException

getNode

public DataNode getNode(java.lang.String path)

get the datanode for this path

Parameters:

path - the path to lookup

Returns:

the datanode for getting the path

getData

public byte[] getData(java.lang.String path,
                      Stat stat,
                      Watcher watcher)
               throws KeeperException.NoNodeException

get data and stat for a path

Parameters:

path - the path being queried

stat - the stat for this path

watcher - the watcher function

Returns:

Throws:

KeeperException.NoNodeException

setWatches

public void setWatches(long relativeZxid,
                       java.util.List<java.lang.String> dataWatches,
                       java.util.List<java.lang.String> existWatches,
                       java.util.List<java.lang.String> childWatches,
                       Watcher watcher)

set watches on the datatree

Parameters:

relativeZxid - the relative zxid that client has seen

dataWatches - the data watches the client wants to reset

existWatches - the exists watches the client wants to reset

childWatches - the child watches the client wants to reset

watcher - the watcher function

getACL

public java.util.List<ACL> getACL(java.lang.String path,
                                  Stat stat)
                           throws KeeperException.NoNodeException

get acl for a path

Parameters:

path - the path to query for acl

stat - the stat for the node

Returns:

the acl list for this path

Throws:

KeeperException.NoNodeException

getChildren

public java.util.List<java.lang.String> getChildren(java.lang.String path,
                                                    Stat stat,
                                                    Watcher watcher)
                                             throws KeeperException.NoNodeException

get children list for this path

Parameters:

path - the path of the node

stat - the stat of the node

watcher - the watcher function for this path

Returns:

the list of children for this path

Throws:

KeeperException.NoNodeException

isSpecialPath

public boolean isSpecialPath(java.lang.String path)

check if the path is special or not

Parameters:

path - the input path

Returns:

true if path is special and false if not

getAclSize

public int getAclSize()

get the acl size of the datatree

Returns:

the acl size of the datatree

truncateLog

public boolean truncateLog(long zxid)
                    throws java.io.IOException

Truncate the ZKDatabase to the specified zxid

Parameters:

zxid - the zxid to truncate zk database to

Returns:

true if the truncate is successful and false if not

Throws:

java.io.IOException

deserializeSnapshot

public void deserializeSnapshot(org.apache.jute.InputArchive ia)
                         throws java.io.IOException

deserialize a snapshot from an input archive

Parameters:

ia - the input archive you want to deserialize from

Throws:

java.io.IOException

serializeSnapshot

public void serializeSnapshot(org.apache.jute.OutputArchive oa)
                       throws java.io.IOException,
                              java.lang.InterruptedException

serialize the snapshot

Parameters:

oa - the output archive to which the snapshot needs to be serialized

Throws:

java.io.IOException

java.lang.InterruptedException

append

public boolean append(Request si)
               throws java.io.IOException

append to the underlying transaction log

Parameters:

si - the request to append

Returns:

true if the append was succesfull and false if not

Throws:

java.io.IOException

rollLog

public void rollLog()
             throws java.io.IOException

roll the underlying log

Throws:

java.io.IOException

commit

public void commit()
            throws java.io.IOException

commit to the underlying transaction log

Throws:

java.io.IOException

close

public void close()
           throws java.io.IOException

close this database. free the resources

Throws:

java.io.IOException